[153] See Western States and Buffalo Advertiser, quoted by Mr. John MacGregor in his “Statistics of the American Lake Trade,” London, 1847.
[154] Batture is the original French word, still retained, applied to the new formation of alluvial soil formed by the capricious action of the Mississippi. The Levee extends from 43 miles below the city to 120 miles above it.
[155] In an address by Mr. Lothian Bell (May 1875), late President of the Iron and Steel Institute of Great Britain, the area of pit coal in the United States is computed at 192,000 square miles, as compared with 8000 square miles in the United Kingdom. Hitherto the expense of working any portion of these vast coal fields was too great to make it remunerative, but, now, the use of coals is being so rapidly substituted for wood in the American steamers that the facilities for working the mines and transporting the coals has marvellously increased within the last twenty years. Mr. Bell remarks, in the same address, that 20,000 tons of coal are sometimes embarked at Pittsburg on a flotilla of flat bottomed boats towed by one steamer and conveyed 1600 miles down the Ohio at something under a shilling a ton, including the cost of bringing back the empty barges.
[156] Between 1816 and 1848 no less than 233 steam-boats employed on American waters exploded, some of them involving terrible disasters, the lowest number during that period being one annually, but sometimes there were as many as ten, twelve, and thirteen in the course of a year. The loss of life in each accident averaged eleven persons, being a total of 2563 human beings killed, besides 2097 persons wounded. In one terrible explosion, that of the Louisiana, on the New Orleans levee, nearly 200 persons lost their lives. See St. Louis Republican and Insurance Reporter (U.S.A.).
[157] In the rule for nominal horse-power, Watt assumed 7 lbs. of steam as a mean pressure.
[158] I am enabled through the courtesy of Mr. Webb, the well-known ship-builder of New York, to furnish in the [Appendix No. 6, p. 600], a description of the engines of the Bristol and Providence, the two finest steamers at present (1875) employed on the line between New York and Boston.
[159] Coals are now worked from mines on the coast, and, from this and other causes, the price of coals on the Pacific coast has been materially reduced.
[160] These “magnificent” vessels are each 5560 tons burden, and are 423 feet in length, 48 feet wide, and 38 feet deep. They are the largest steam-ships that have ever carried the American flag. It is confidently believed in America, that the running time from Hong Kong to San Francisco, viâ Yokohama, by these vessels will be reduced to within twenty days; and they are guaranteed by the builder, under a heavy penalty, to make fourteen and a half knots per hour. The City of Pekin, on her trial trip, made fifteen knots an hour, with fifty-three revolutions per minute and 57 lbs. of steam. This company has now in course of construction another three steamers similar in size; all are being built of iron at Chester, Pa., U.S. Each vessel will have capacity for 800 passengers, and 3000 measurement tons of freight.
[161] The advantages of this system of trussing are described by a practical authority, as follows: “Running fore and aft, and constituting the frame of the sides of the ship, are two arched trusses of wood and iron, of the most ingenious construction. The vertical depth, from the crown of the truss down to the level of the keel, is about 53 feet. In the truss is also interwoven a counter arch, the trusses, therefore, not only prevent the sinking of the two extremities and rising of the middle, but they likewise prevent any rising of the extremities, and sinking of the middle of the ship, and thus effectually prevent any tendency to bend or break in the direction up or down in a fore and aft vertical plane; and, by a most perfect system of lateral trussing interwoven with the tiers of beams, she is prevented from bending or breaking in the direction of a horizontal plane, running fore and aft through the ship. Where strain by tension or pulling is exerted, wrought iron is to be used, and where thrusts or compression is exerted, wood is used, and where both compression and extension are felt, wood and iron together are used.”—Address by Captain T. J. Cram, delivered at the Board of Trade Room, Philadelphia, July 11th, 1860.
[162] So far as regards the stability of the proposed vessel, Captain Cram, who was a member of the United States’ Corps of Topographical Engineers, remarks, in the lecture on her, delivered in 1860 at Philadelphia, as follows: “She is to be a four-storey ship. Commencing at the bottom and going upwards we have the first storey, a hold, 16 feet high in the clear, with ample room for the machinery, boilers, and coals, and for a large quantity of freight besides. All this great weight of engines, boilers, coals, and dead weight freight, which is to be stowed in the very bottom of the ship, will act as ballast placed in the right position to insure stability and to relieve the ship from that dangerous topheaviness usually observed in many sea-going steamers.”